Apparatus for the control of highway crossing gates



P. H. CRAGO Feb. 6, 1945.

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING GATES Y Filed 00 28, 1942 wan INVENTOR PaalH. Ci ayo. BY 1. H15 ATTORNEY.

Patented Feb. 6, 1945 APPARATUS- FOR THE CONTROL OF HIGH- WAY CROSSING GATES Paul H. Crago, Wilkinsburg, Pa. Assignor to The Union .Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application ctober.28, 1942, Serial No. 463,632

' 7 Claims.

My invention relates to apparatus for the control of highway crossing gates, and has particular reference to systems for automatically controlling such gates by railway .traffic. More particularly, my invention relates to the provision of novel and improved systems for controlling the operation of'highway crossing gates at the intersection of a highway and a multiple track railway.

A control system of the class described involves crossing gates positioned at the intersection of a railway and a highway. These gates'are normally held in a vertical or non-obstructing position as long as the approach track section provided fol each track is vacant, and are lowered to a horizontal or obstructing position whenever an approach section isentered by a train. The approach sections are each of "a length sufiicient to assurethat the gates will reach their obstructing positions not less than a predetermined interval prior to the time that the head end of the train enters the intersection, Warning devices, such as bells or lights or both, are usually provided at or near the gates and are caused to operate during the time the gates are being lowered, as well as for an interval before the lowering operation is initiated. This operation of the warning devices for a short interval prior to the lowering of the gate arms, provides a preliminary warning period for informing highway traflic that the gates are about to be lowered, and thereby guards against lowering the gates immediately in front of or on top of highway vehicles.

The system also involves operating mechanisms for raising the gates to their vertical positions after each train clears the intersection. This operation requires several seconds to complete,

and during this interval a second train might enter an approach section before the gates reach their vertical positions following the passage of the first train. In such an event, it is undesirable to stop operation of the gates and permit them to drop immediately, since highway, traffic would then have no warning of .the release of the gates and might become trapped on the intersection or struck by the descending arms.

In view of the above-mentioned and other important considerations, an object of my present invention is the provision of apparatus for the control of highway crossin gates incorporating novel and improved means arranged to insure that the movement of a gate to its non-obstruct ing position willbe completed once it has been initiated following the passage of atrain.

An additional object of my invention is the provision of novel and improved apparatus for the control of highway crossing gates arranged to utilize the electric motor of the gate as a dynamic brake when the gate i operating from its nonobstructing to its obstructing position.

In practicing the invention, the above-mentionecl and other important objects and characteristic features which will becomereadily apparent from the following description, are at tainedby providing each track with a checking section through which a train must travel to The arrangement is such that the other relay is picked up when a train vacates an approach sectionprovided that all of the approach and checking sections are then vacant.

I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view illustrating one form of apparatus embodying my invention.

Referring to the drawing, the reference char-' acter X designates one track and-the reference character Y designtaes another track of a stretch of multiple track railway. Trafiic normally operates over track X the eastbound direction as indicated by an arrow associated with track X in the drawing, while traflic normally operate on track Y in'the opposite or westbound direction as indicated by the associated arrow. Thetracks ,X and Y are divided by insulated joint 2 into a plurality of tracks sections, designated by the reference characters T with suitably distinguishing prefixes. Each of these sections is provided with a closed circuit track circuit including a track relay designated by the reference character TR with a prefix corresponding to the prefix of the associated section, theassociation of each relay, with its section being indicated conventionally in the drawing by dotted lines. Relays 2TR I and 3TB, as indicated in the drawing, form the operating windings of an interlocking relay 23TR, whil relays 5TB. and '6TR form the operating winding of another interlocking relay 5-6TR. These interlocking relays maybe of the type disclosed, for examplefin Letters Patent of the first to be released, front contact I9 associated therewith opens, and the armature of. relay is latched up so that when the latter relay sub-; sequently becomes released with relay 2TB still released, front contact 20 operated by relay 3TB is held closed.

The stretch of track is intersected at grade by a highway H adjacent to .theexit'ends of. sections 2T and ST, respectively, hence section, 2T may be considered an approach section for rail- Way rams npm shine t i r e t onst a s X th stb unidi ec iomthat t e ftw right as viewed in, the; drawing, whereas section 5T may be consideredanapproach section for, westbound trams approaching the intersection on track Y.; Sections lT and '4T, through which trains operating-in ,thenormaldirection of trafiic on tracksX and Y, respectively, musl traversej inorder to reaeh the associated approach sec i s. il ,b med re naf r hec nasections.

The. i t rsec1 m sr mz d q,- t hway; ossinssat s, and G l e t nede hev nt -i section onopposite; sides of the railway; Each gate has agate arm biased to a horizontallor obstructmg osition in which it obstructs high-: way traflic and anoperatingmechanismefiective.

tooperate thefarm -to a vertical ornon-obstructing position inwhichthearm clears the highway; For conyenience the horizontal; position 1 of, the; gatearm will be termed the position while the; vertical position will be termed the 90 position The operating mechanisms. otthe gate are, pref-f erably alike and eachmay comprise; any suitable.

ime s nal actu tin mechanis h ea. f r

am-9 1e,, tha own. n Letters Patent of; the; grantedMay 4, 1915,.

United States No. 1433p to;, Jol 1r 1 -P.Coleman. In the,applicationoi the t nt, t e to a c oss n sate-r. it. i be understood that the gate arm is an 'extendedform of; the seniaphoreof thepatent, Only, the. mch

anism and,controllingapparatus' for gate GI. are shown in the drawing for the, sake of: simplicity sincethe two alie;. may be. alike and the illustra-. tion of the mechanism andcontrol of gate G2 would be but a duplication of that-shown for gateGL.

r The gatemechanismof gate..G.l .comprises a motor Ill operatively connected withgateGlfor operating it from its horizontal. or;,0 position to its vertical or 90 position; a slot magnet ll hav--.j

ing twowindings l2 and I3 and efiective when the magnet isenergized to hold orlatch thegatea in its 90? position; andav circuit controller J oper atively connectedwithxthe gate, and having contacts selectively closed in accordance with the position of the gate. Associated with-the gate mechanism is a, snubbingirelay SR;

'I'he crossing. gatemechanism is controlled by.

a. control relay XR provided .with-a pick-up circuit whichmay be traced from one terminal B: of a suitable source of current, such as-a-battery notvices, such as a bell 23 and a plurality of lamps 28. The bell. 2.3. is energized over'a circuit extending from terminal B through back contact Zdof relay XR, contact 252621 (closed at 3 to 92) of controller J, and the operating element of bell 23 to terminal- C, hence the bell is. energized during the preliminary period and while the gate operates from its vertical or 90 position tov a position, such as 3-", just short of its horizontal position. The. lamps. 28 are energized overa circuit having two paths, oneincluding back contact 29 of relay XR, and the other'including; contact 3ll3l---32 .of controller J, hence the lamps. are. energized whenever relay XE. is released or when-1; ever the gate arm is intermediate its 0 and .88; positions. Although. only .twolamps have. been illustratedJt. is to beunderstoodgthat:v any desired number may be provided, mountedona pole, gate arm, or' wherever desired. Also',.,. the lamp. control circuits maybe governed by a. flasher relay, in accordance. with the usual practice,.but-. since the particular arrangement incorporating.

' the. flasher relay forms'nopartof my present.in-.

' simplify the description.

shown, through front contact, [5; of; relay |TR,,:.

f ront. contact; I 6-of relay 4TB, front flagmancon- In the normal condition of the, apparatus, as:

represented in the drawing, the stretch of track comprising. sections. IT. to BT', inclusive, is un-.-

occupied; relay XRxis pickedup; gate. GI is in its:- vertical or position; bell 23 and lamps 28are deenergized; and winding lz of the. slot magnet. is energized over a circuit which extends from terminal Btthrough front contact. of relay XPR" and winding 12 of magnet l l to terminal C. This winding is the holding Winding of magnet H and is .efiective when. energized to hold the; gate. arm latchedin'its verticalaposition.

When a. trainoperating: over either track in. the normal direction oftrafiic. enterseither checking section IT or 4T'in approaching the inter-- section, the track relay of-that section releases but the operation of the crossing gates isnot: initiated until the approach se'ctionof that track is entered. For example, if "an eastbound train operating on track X enters section IT, relay ITR: releases to open the previously traced pickup circuit of relay XR at front contact 15, but relay XR isheld-energized over itsstick circuit including its own-front-contact 2h When-how ever, the train entersapproach section 2T; relay I circuit including a resistor 35 and back contact 36 of relay SR. The resistor 35 places a heavy load on motor. IIl'which now functions as a generator and therefore tends to brake or retard the descent of the arm.

When the arm reaches its 3 position, contact 25-26-21 opens the circuit of bell 23-to end its operation; After the arm drops to its full horizontal or position,it remains there until relay XR picks up. This event occurs when the train vacates approach section 2T, provided that all of the other approach and checking sections are vacant. If, for example, approach section T and checking sections 4T and IT are vacant when the eastbound train vacates section 2T (section 3T of course being occupied), then the closing of flagman contact III of relay 2TR, with flagman contact 20 of relay 3TR held closed in its latched position, results in the previously traced pick-up circuit of relay am being completed and relay XR picks up to close its front contact 2| and thereby complete its stick circuit. In addition, front contact 24 of relay XR closes to complete a circuit extending from terminal B through frontv contact 24 of relay XR, contact 31-38-39 of controller J and the winding of relay SR to terminal C. Relay SR accordingly picks up to remove the shunt path on motor I0 and to energize that motor over a circuit extending from terminal B through front contact 24 of relay XR, contact 31-38-39 of controller J, front contact 36 of relay SR and motor I0 to terminal C. Also, relay XPR is energized and it in turn energizes winding I2 of magnet II, but that magnet does not pick up since winding I2 is proportioned to be effective to hold but not to pick up the armature of the magnet. The gate arm is then operated toward its vertical position, and at this time the lamps 28 areenergized over their circuits including contact 30-3I-32 of controller J, but bell 23 is silent. At the 85 position of the arm, contact 40-4I-42 of controller J becomes closed and winding I3 of the slot magnet becomes energized in multiple with winding I2 over a back contact 43 of the slot magnet. When the slot magnet armature is picked up by the cooperative action of the two windings I2 and I3, back contact 43 opens to deenergize winding I3 but the armature is held attracted by its holding winding. I2 to maintain the slot magnet conditioned to latch the gate arm in its picked-up position when the 'gate reaches its 90 position. contact 30-3I-32 of controller J opens to interrupt the circuits for lamps 28 and contact 31-38-39 opens to interrupt the circuits for relay SR and motor Ill, whereupon the motor becomes deenergized and relay SR releases to reapply the snubbing circuit path to the motor. The gate then drifts by momentum to substantially its 90 position.

In the event that a second train is in the other approach section ST or either checking section IT or 4T at the time that the first train vacates section2T, relay XR. will not pick up because its 'pick-up circuit will be held open at the front contact of the relay associated with that occupied section. For example, if a following eastbound train enters section IT before the first train vacates section 2T, then relay ITR is released and holds open the pick-up circuit of relay XR'at front contact I5; and similarly if a westbound train operating on track Y occupies either section 4T or 5T before the first train vacates section 2T, then the pick-up circuit of relay XR is held open at front contact I6 of'relay 4TR or front contact I8 of relay 5'IR, as thecase may be. In this manner the gate ismaintained in its horizontal position by the second train.

At the 88 position,

It is, of course, apparent that the apparatuswill operate for westbound trains operating on track Y in substantially the same manner as hereinbefore described for eastbound trains operating on track X, so that further detailed explanation is deemed unnecessary.

The approach sections 2T and 3T are ofa length sufficient to insure that the crossing gates will occupy their obstructing positionsfor a predetermined interval of time prior to the head end of a train entering the intersection. The other two sections IT and 4T may have any convenient length but each is preferably longer than the distance a train normally covers during the time interval required to raise the crossing gates. These proportions, which may of course be varied, are therefore such as to prevent initiation of the operation of the gates to the raised positions when the first train vacates its approach section should a second train be operating on either track within a distance less than that comprising an approach section and.

the length of track traveled by the second train in the time interval required for the gates to be operated to the raised position. It follows, therefore, that the gates will be raised to their vertical positions only in the event that conditions are such as will enable the gates to reach their vertical positions before a second train will cause them to drop, whereby there is avoided the possibility of having the operation of the gates to their vertical positions terminated without warning to the highway traffic.

The exit sections 3T and BT are provided to take care of movements against the direction of traflic on tracks X and Y, respectively, and the relays 3TR and GTR are arranged so as to release the gates whenever either section is entered by a train operating against the current of traffic on the associated track. The control effected by relays 3TR and BTR substantially corresponds to that common in practice and will not be described in detail since it forms no part of my present invention.

Although I have herein shown and described only one form of apparatus for-the control of highway crossing gates embodying my invention,

it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a highway crossing protective system provided for a stretch of railway track intersected at grade by a. highway and provided at such intersection with a highway crossing gate biased to an obstructing position; said gate having an operating mechanism comprising amotor operable to move the gate to a non-obstructing position, aslot magnet operable to hold the gate at its non-obstructing position, and a circuit controller operated by the gate; said stretch of track having associated therewith anormally energized control relay governed by traffic operating over said stretch; said slotmagnet having a control.

circuit including a front contact of said control relay and a contact of said circuit controller closed only in the non-obstructing position of the gate; the combination with the foregoing apparatus of a snubbing relay, a control circuit for saidsnubbing relay includingta .frontcontactof said control. relay and-'a contactofi saidi ci-rcuit controller'rclosedin: all positionsofi the :gate ex.- cept its said .non obstructing:position, an-operatingeircuit for-said motorin-cludinga front contact of said snubbing:,relay,;=and-a snub: circuit connected. across-said motor through a back con-- tactzof said snubbingrelay; and including a re-.

sistance providing; a. load. for theregenerative braking of said motorduringzm'ovement ofrsaid gate from its saidznon-obstructing; to itssaid obstructing: position. a V

2. In. combination with a. stretch of. railway trackvintersectedr at grade by a highway,- and divided into a. first. andv a. second track section traversed in. the order. named by; a train an:- proaching the intersection; a. track circuitincluding atrackrelay iorz'each of: said sections,

ahighway crossing gate: ati suclrintersectiorr hav- 1 ing agate. arm biasedtto: an obstructing position;

anelectric motor operatively'connected'with said arm for operating said arm fromsaid obstructing to anon-obstructing position, a'slot magnet effective when energizedto latch said arm in its 1 non-obstructing? position, a controller contact operativelyconnected withsaid arm and closed I in all except the non-obstructing position of said 5 arm, a snubbing; re'lay, asnub circuit including a n back. contact of saidsnubbing relay for connecting. a resistor across said; motor for providinga 1 load for the dynamic brakingof saidmotor, a control relay having. a. firstcircuit'including' its own front contact and a frontcontact of the track relay of said; second section, a-second circuit for said control relay including'in series a contact of each of. said. track relays, a circuit for said slot magnet including a front contact of said. control relay, a circuit for. said snubbing i relay includin a front contact-ofsaidcontrol relay andsaid controller contact and acircuit for said motor including a: front contact-oi said snubbing relay.

3. In combination witha. stretch -of railway track intersected at grade by ahighway and: divided intoa first-and a secondztraclc sectiontray:- ersedin the ordernamed by a train approaching the intersection, a track circuitincluding atrack relay for each of said sections, ahighwaycrossing gate. at suchintersection havinga gate. arm :bi-' ased to an obstructing-position; anelectric. motor operatively connected: .with saidarm for operating said arm from said. obstructing, to anonobstructing position,.aslotmagneteffective when energized to latch said arm in its non-obstructe ing position, a controller contact. operativelyconnected with saidarm .and closedinall exceptthe non-obstructing position of said arm, a snubbing 1 relay, a snubcircuit including aback, contact of said snubbing relay for connecting aresistor and means for energizing. said snubbing relay in multiple with said motor. over a circuit including in series a frontcontact of said controlrelay and said controller contact.

4. In combination with a. stretch of railway trackco-mprising. apluralityof tracks over which jtrafiic normally. operatesin predetermined directions, each of said tracks being; intersected at gradebwahighway: andceacn being divided. into a: first andiaysecond' tracks section traversed in the-order namedybytrains-approaching theintersection in the" normal direction-of traffic Orr-that energized .to latch said arm in its nonobstruct? ing position, a controller contact operativelyv connected with-said arml-andcloseda in -all except thenon-obstructing position of said. arm, asnubbingrrelay, a snub circuit including .a back Icontactofsaid snubbingrelay. for connecting, a. res sistor across saidmotor for providing a load for the dynamic.brakingtof saidmotor, a control relaya first circuitinclud'ing, its. own =front contact and a front contact of each of the track relays ofv said second -sections,. a. second. circuit forsaid' control relay including, inseries a contact of eachof the track relays of'said first and second sections, a, circuit for saidslot magnet, in.- eluding afront coritactof said control. relay, a circuit for said snubbing. relayincluding-a-iront contact" of said control" relay. and said controller contact, and a circuit for saidmotor includingvv a front contact of: said 'snubbingrel'ay.

5;. In combination with a stretch of railway track having a plurality of tracks over eachof which trafiic normally, operates in a predetermined directiomneach of said tracksbeingintersected at grade by a highway and'each' being divideddnto' a first and a. second track. section traversed'inthe order n'amed'by trains approaching thev intersection in the predeterminedf direction oftraffic for'that track', a track circuit'ine eluding a track relay for each, of said section's; a highway crossing gate at such intersection having agate" arm biasedt-o' an obstructing posi-' tion, an electric motor operatively connectedwith said arm for operating said armfrom said'obstructing to a nonobstructing-posit'ion, a slot magnet effective when energi'zedzto latch'saidarm in its non-obstructing" po'sit'io'n; a controller contact operatively'connectedwitli said" arm and closed in all except the non-obstructing "position ofsai'd arm, a snubbingrelay; a snub circuit including: a back contact of saidsnub'bin'g relay for connecting a resistor across said motor for providing-a, loadfor thedynamic braking of said motor; a control relay having afirst" circuit in cluding its own' frontcontact and a front contactof-J each of the track relays of said second sections, a second'circuit forsaid control relay including in series-a contact of each of: said traclcz'relaysi of: said first: and- -second sections;- a I circuit; for said slots magnet. including a front contact of said control relay, andlmeans for energizing. said? snubbingarelayc'in multiple: with said-motor over a circuit including 'in series a front: contact ofvsaid:.-control= relay and said: Icontrollercontaot.

6; Inrcom bin ationrwith a stretch. or railway track having aplurality of tracksover each of which; traffic normally? operates in a predetermined direction; each 01'"? saidztr'acks beingdnten sected. atxgrade a highwayzan'd "each: being divided intoa first-and a second: section traversed inthe order named by trains approaching the; in tersectiondn the. predetermineddirectionzof trai no for: that tracka track circuit-including; a

.trackmelay, for. each off-saidsections; a highway crossing gate at said intersection, a control relay, means governed by said control relay for operating said gate, a circuit for said relay including its own front contact and a contact of each of the track relays of said second sections, and a pick-up circuit for said control relay including a contact of each of said track relays of said first and second sections whereby to preventoperation of said gate when any of said first and second sections is occupied.

'7. In a highway crossing protective system provided for a stretch of railway, track intersected at grade by a highway and provided at such intersection With a highway crossing gate biased to an obstructing position; said gate having" an operating mechanism comprising a motor operable to move the gate from its obstructing to a non-obstructing position, a slot magnet operable to latch the gate at its non-obstructing position, a,circuit controller operated by the gate, and control means for controlling said gate and having a first and a second position; the combination with the foregoing apparatus of a control circuit for said slot magnet including a contact of said control means closed only in its said first position and a contact of said circuit controller closed only in the-non-obstructing position of the gate, a relay, an operating circuit for said relay including a contact of said control means closed only in its said first position and a contact of said circuit controller closed in all positions of the gate except its said non-obstructing 

